The present invention relates to methods and systems for screening eyes for indications of abnormalities. In a preferred aspect, the invention is configured for specific application to screening of preschool and school-age children to provide detection of ocular disease, abnormalities and conditions that may lead to amblyopia. Further, the present invention has application for general vision screening to detect vision problems.
Detection of ocular disease and abnormalities in preschool children is important to prevent long-term vision impairment. During early development, the child""s brain attempts to process visual information that is received in both of the child""s eyes. However, if an ocular malady or impairment exists in one of the child""s eyes which goes untreated for an extended period of time, the brain eventually stops processing information from the diseased eye, and leads to the severe ocular condition of amblyopia. Detection and treatment of amblyopia is required at an early stage of childhood development before the condition becomes irreversible.
While early detection of ocular disease and abnormalities in preschool and schoolage children is desirable, the ability of an ophthalmologist, pediatric ophthalmologist, optometrist, pediatrician, family practitioner, or other trained health care worker, henceforth collectively called health care professional, to identify certain eye maladies in young children is complicated by the age of the child, and in many cases, the inability of the child to communicate with the health care professional. Common diseases and abnormalities which must be detected and treated in children include misalignment of the optical axes of the eyes (strabismus), refractive errors which include nearsightedness (myopia), farsightedness (hypermetropia), astigmatism, and anisometropia (unbalanced refraction), opacities (like cataracts) and other conditions which reduce vision.
In the past, ocular screening of a patient""s eyes has been done manually where a physician observes reflections from a hand-held light source, and more recently by observing recorded images of the patient""s eyes on conventional film (35 mm or Polaroid(copyright)) or a charged coupled device (CCD). In the case of recorded images, a flash beam of light is positioned to travel off of, but nearly coincident with, an optical axis defined by the camera. The incoming flash beam of light is refracted by the cornea and lens of the patient""s eye and falls generally on the pigmented macula and fovea of the patient""s retina. An image of the illuminated retina, called the retinal reflection or retinal reflex, is recorded by the camera. A portion of the incoming light is reflected from the front of the cornea as a corneal reflection or corneal reflex. Additionally, a picture of the area around the eyes (eye lids and orbital structure) is recorded by the camera. The recorded image is stored for later evaluation by a health care professional trained in the art of vision screening. Based on an evaluation of the corneal and retinal reflections, which may take days or even months to develop and review, the health care professional is able to identify certain ocular maladies.
The benefits of vision screening for young children has been long recognized. However, such screening is not cost effective on a wide scale if conducted by professionally trained eye care specialists, such as optometrists and ophthalmologists. In an effort to identify young children demonstrating risk factors associated with common ocular diseases and abnormalities, mass screening programs have been attempted.
At least one goal of these screening programs is to provide a cost effective and accurate screening for certain eye maladies. Additionally, the false negative results of the screening process must be maintained within a narrow range to limit the number of children who are improperly assured no vision problems exist. Further, false positive results must also be minimized to limit unnecessary referrals to medical professionals. At least one report on prior eye screening programs cautions that an overreferral pattern of xe2x80x9cnormalxe2x80x9d patients could flood the health care system and misappropriate health care dollars.
Early efforts at creating effective eye screening relied on a manual review of Polaroid(copyright) type photographs of children""s eyes. A study has evaluated the MTI photoscreener in a patient population of 15,000 children aged 6 to 47 months. A relatively high percentage of children (nearing 5%) had photographs taken that could not be used for photoscreening. Thus, these individuals received no benefit from the screening process. Further, the study reported that only 60% of those children with a positive screening result actually had an eye disorder diagnosed after a follow-up examination. An additional factor, and potentially more significant for patient health, was that assuming amblyogenic factors are present in approximately 5% of the population, the reported photo screening method missed as many children with these factors as they identified. The lack of quality assurance inherent in these types of photo screening methods has led to criticism since there is a high degree of subjectivity and interobserver variability leading to unacceptable levels of false negative and false positive test results.
Notwithstanding the advancements made in the prior art in the field of ocular screening for children, there is a need for an ocular disease and abnormality detection method which improves the accuracy and reliability of the screening process. The screening process should also be cost effective for wide scale application and use.
One object of the present invention is to provide a method for accurate screening of eye images to detect abnormalities and disease. In one aspect of the invention, an image of an eye is obtained and digital data corresponding to that image is transmitted to a central facility. Through an automated process, the central facility selects a qualified reader and transmits the image data to the reader for review and analysis. The reader inputs their analysis of the patient eye image and transmits that information electronically to the central facility. The central facility automatically tabulates the readers analysis and generates a report which is then transmitted to the patient. In a preferred aspect of the invention, the reader is periodically tested to assess skills and accuracy of reading images demonstrating known patterns of ocular disorders. Further, in a still more preferred aspect, the central facility routinely evaluates reader results and compares these results to expected results based on statistical assumptions to determine if reader results are within acceptable margins.
In still a further aspect of the invention, a method is provided for screening of patients for ocular disease and abnormalities at locations remote from skilled analyzers trained to interpret eye images. This method includes providing a remote site with a photoscreening device for generating images of corneal and retinal reflections from a patient eye and a device for recording such images. An image of the eye including corneal and retinal reflections is obtained and the information is transmitted to a central data facility. The central data facility automatically selects an analyzer for evaluating the image of the patient""s eye. The digital information of the patient""s eye is transmitted to the image analyzer. In a preferred aspect, the image of the patient""s eye is accompanied by a standardized form which may be easily completed by the analyzer to insure consistent descriptions of the observed abnormalities. Information related to the presence of abnormalities in the patient""s eye is generated and the information is transmitted back to the central data facility. The central data facility may then provide the patient or requester with the results of the screening. In a preferred aspect, the prior accuracy or educational level of the analyzer is considered by the central data facility and if a minimum threshold is not met, the patient""s information will be transferred to a second analyzer to obtain a second opinion. In still a further preferred aspect, a percentage of each of the images reviewed are forwarded to second reviewer for a second opinion. The percentage of images sent for second opinions may be controlled to vary depending on reviewer training and accuracy demands. In this preferred aspect, the first reader""s analysis and the second reader""s analysis are compared and if identical the information will be transmitted to the central data facility and on to the patient. However, if discrepancies are detected, the method may resolve the inconsistencies prior to sending the results to the patient.
In a further aspect of the invention, a system is provided for eye screening. The system comprises a remote data entry device and eye image acquisition device. At least one of the devices is electronically connected to a central data facility. The central data facility may be electronically connected to a plurality of remote readers.
These and other objects of the present invention. will become apparent from the following figures and description of the preferred embodiments.